Jackshaft Built in jackshaft??

Discussion in 'Transmission / Drivetrain' started by mnbiker, Dec 13, 2007.

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  1. mnbiker

    mnbiker Guest

    Will the bearring and weld hole if you take the crank out and but in a jackshaft? Also does regular bike chain work or is it to weak?

  2. JemmaUK

    JemmaUK Guest

    It would depend on the power you are putting through it and it would be advisable to put some bearings in there too although it would probably work with such as the happy time or tanaka engines etc... I wouldnt want to put too much HP through it.

    Also if you did go down that route you would have to align things properly - torque twist might hurt the frame.

    Finally, and the biggest problem is that of legality. The reason that autocycles and cyclemotors had pedals was that they would have been classed as motorbikes otherwise. This is also the case as I understand it in alot of the US states and most definately in the UK.

    It is however possible that the pedal crank could be used as a jackshaft - with the engine and pedals using the same driveline - however that causes its own problems..

    Jemma xx
  3. mnbiker

    mnbiker Guest

    Yeah but this bike ive had for 7 or 8 years and if getting rusty sitting there for the past 2 years so id figure i might try some things to see how they worked out. The main reason for concidering this is because it has rear suspension and wanted to have chain drive but with no tenchioner. The motor im planning on using it a snowblower motor from a toro S-200 http://www.wfmiller.com/parts-detail.asp?VehicleID=18004 . Only 3hp rated but cant be much more. do you think regular bike chain will hold up to this motor. Im going to go with cent clutch or direct drive havent made up my mind. I think cent would be smoother and easier on jackshaft/crank hole but direct would put more power to the ground.

    So what im asking is
    1. Is the motor to big? (i dont think so but you guys are the bike experts)
    2. What would be better cent clutch or direct?
    3. Finally, will regular bike chain hold up?
    Last edited by a moderator: Dec 15, 2007
  4. Alaskavan

    Alaskavan Guest

    I'll take a stab at answering your questions.
    1. Is the motor too big?
    Physically? The link doesn't give actual dimensions, but I'd guess that a 3hp Tecumseh isn't huge. It should fit on some bikes.
    Legally? It exceeds hp limitations and probably cc limitations for a motored bike. (I realize that you are probably not concerned about that.
    2. What would be better cent clutch or direct drive? Direct drive presents problems for both starting and stopping, and it would eat the chain. If you can figure out how to overcome those problems, it would deliver more power to the ground. Cent clutch is easier and more practical. (It will probably not leave as many scars).
    3. Will the regular bike chain hold up? Yes, If you ride very gently. If not, no.
    All this is just my opinion.
  5. mnbiker

    mnbiker Guest

    No the power of the unit on the crank hole. I got it to run and its mounting holes are on the crank side and the bike i have doesnt have alot of open space between the frame rails so it will work perfect ill bot it on side ways.

    I got this running tonight and i noticed the belt tentioner, maybe i could use this to engage and dis engage the belt and just have it be manual, but then will the belt slip if the bike and motor speed arent the same and without pedals its hard to get moving fast.

    Ill measure the crank tomorrow and see if i can find a clutch for it.
  6. ibdennyak

    ibdennyak Guest

    Have one of those myself. Pretty durable little engines. 98cc, and they are 3 hp but at 4400 rpm. Also have an old bike sitting around that has a retro look to it. I've been thinking about putting them together too. Engine is fairly compact, but in my case I will have to shorten the crankshaft to fit between the pedals. I'm thinking direct belt drive on mine with about a 14 inch driven pulley, it came out to about 35 or so mph at max rpm. Just need some ambition. :rolleyes: Keep us apprised of your progress.

  7. JemmaUK

    JemmaUK Guest

    Interesting given the RPMS to power ratio - and CC. Sounds almost like a licenced version of one of the old Villiers...?

    The only thing that worries me is the 'rust' - is it surface or structural. Even if it is the former it will weaken the structure and we have had at least one instance of a perfectly solid frame snapping under the stress of a mere 1.6hp...

    Jemma xx
    Last edited by a moderator: Dec 16, 2007
  8. mnbiker

    mnbiker Guest

    Yeah but the frame is similar to this one http://www.theinfoline.com.au/pictures/e_bike.jpg , its a rather big frame and if it does brake then oh well, the bike had onyl front brake the forks are worn out and bent the derailor is gone and broken the only real goos things on it are the bedals which im using for a different bike and the seat which i will keep very comfy.
  9. mnbiker

    mnbiker Guest

    also the motor is self throttled at the time i may be able to use that at start up, like for chain saws have the smae try og thing but only at 1/2 throttle.
  10. ibdennyak

    ibdennyak Guest

    Yup, actually the governor was the original reason I bought it. I planned on using it on an alternator for a constant voltage output on the electric. It is easily disabled by connecting a throttle cable to the carb butterfly though. Geez, what happened to the idea of saving money by riding a bike? :rolleyes:

  11. mnbiker

    mnbiker Guest

    haha really, i know im very firmilar with motors, but i just went and blew up my sno pup motor and im going to see if this one will fit. It had low compression so i was always messing with the mix screws and i accidently leaned it out and boom blakc smoke and there goes that parade.